Bresser Biorit Mode D'emploi page 11

NOTE!
When you switch the Objectives pay close
attention that the Objectives will not hit the
preparation. Damage to your preparation can
be avoided by following this advice.
Insert the 5x eyepiece (Fig. 2, 1) in the Barlow lens (Fig. 2, 3).
Take care that the Barlow lens is inserted completely in the
monocular barrel (Fig. 2, 4).
4. Observation
After you have set up the microscope with the corresponding
illumination, the following principles are important: Begin each
observation with the lowest magnification so that the centre
and position of the object to be viewed is in focus. The higher
the magnification, the more light is required for good picture
quality. Begin with a simple observation. The colour filter (Fig.
1, 10) under the microscope table aids in viewing very bright
and transparent objects. Just select the right colour for the
specimen in question. The components of colourless / trans-
parent objects (e.g. starch particles, single-cell specimens)
can thus be better recognized. With the mechanical desk (Fig.
5) you can look at your prepa ration in a precise position and to
the exact millimeter. The object is placed between the clamps
on the mechanical desk. Move the object by using of the axis-
adjustments (Fig. 6, X/Y) directly under the objective. With the
built in vernier (Fig. 6 B) at both axes you can now specifically
set and shift the object. It can now be viewed with different
magnifications. Look through the eyepiece (Fig. 1,1) and turn
carefully the focusing wheel (Fig. 1, 9) until you can see a sharp
picture. Now you can get a higher magnification, while you
pull out slowly the Barlow lens (Fig. 1, 2) of the monocular
barrel (Fig. 1, 4). With nearly entirely pulled out Barlow lens the
magnification is raised by 2x. For still higher magnification you
can put the 16x eyepiece into the holder and set the objective
revolver to a higher position (10x / 40x). In this setting the mag-
nification raises also up to 2x by pulling out the Barlow lens.
TIP:
i
Depending on the preparation higher magnifi-
cations do not always lead to better pictures.
Please notice: With changing magnification (eyepiece or
objective lens changes, pulling out of the Barlow lens) the
sharpness of the image must be newly defined by turning
the focusing wheel (Fig. 1, 9).
NOTE:
Please be very careful when doing this. When
you move the mechanical plate upwards to fast
the objective lens and the slide can touch and
get damaged.
5. Viewed Object – condition and preparation
5.1 Condition
With an ordinary magnifying glass, we preferably view obscure
items like little animals, plants etc. Here light shines on the
viewed item, gets reflected and gets through the lens into our
eye (Top illumination principle). With a biological microscope,
a so called transmitted light microscope, only transparent
items can be observed.
Light gets through the item, becomes magnified by the objec-
tive and the eyepiece and gets in our eye. Many small water
organisms, small plant parts (e. g. moss leaves) and finest ani-
mal components are naturally transparent; other ones must be
accordingly prepared. By means of a pre-treatment or pene-
tration with suitable materials (media) some specimens can be
rendered transparent or we cut finest slices off of them (hand
cut, Mikrocut) and then examine these. The following instruc-
tions make us familiar with these methods.
5.2 Manufacture of thin preparation cuts
As already before implemented, as thin cuts as possible are
to be manufactured from an object. In order to come to best
results, we need some wax or paraffin. If no such material is
contained in your microscope set, then you take simply a can-
dle. The wax is given to a pot and warmed up over a flame.
The object is dipped now several times into the liquid wax. Let
the wax become hard. The object is now inserted through one
of the holes in the Mikrocut. By turning the razor, thin slices
will be cut off now. These cuts are put on a glass slide and
covered with a cover glass.
DANGER!
Be extremely careful when using the knives/
scalpels or the MicroCut. There is an increased
risk of injury due to the sharp edges!
5.3 Manufacture of an own preparation
Put the object which shall be observed on a glass slide and
give with a pipette a drop of distilled water on the object (Fig.
17). Set a cover glass perpendicularly at the edge of the wa-
ter drop, so that the water runs along the cover glass edge.
Lower now the cover glass slowly over the water drop (Fig. 18).
For permanent conservation of preparations give a little gum
media on the edges of the cover glass.
6. Experiments
If you made yourself familiar with the microscope already, you
can accomplish the following experiments and observe the re-
sults under your microscope.
6.1 Newspaper print
Objects:
1. A small piece of paper from a newspaper with parts of a
picture and some letters,
2. a similar piece of paper from an illustrated magazine.
Use your microscope at the lowest magnification and use the
preparation of the daily paper. The letters seen are broken out,
because the newspaper is printed on raw, inferior paper. Let-
ters of the magazines appear smoother and more complete. The
picture of the daily paper consists of many small points, which
appear somewhat dirty. The pixels (raster points) of the maga-
zine appear sharply.
6.2 Textile fibers
Objects and accessories:
1. Threads of different textiles: Cotton, line, wool, silk, Cela-
nese, nylon etc.,
2. two.needles.
Each thread is put on a glass slide and frayed with the help of
the two needles. The threads are dampened and covered with
a cover glass. The microscope is adjusted to a low magnifica-
tion. Cotton fibres are of vegetable origin and look under the
microscope like a flat, turned volume. The fibres are thicker and
rounder at the edges than in the centre. Cotton fibres consist
primary of long, collapsed tubes. Linen fibres are also of veg-
etable origin; they are round and run in straight lines direction.
The fibres shine like silk and exhibit countless swelling at the
fibre pipe. Silk is of animal origin and consists of solid fibres of
smaller diameter contrary to the hollow vegetable fibres. Each
fibre is smooth and even moderate and has the appearance of
a small glass rod. Wool fibres are also of animal origin; the sur-
face consists of overlapping cases, which appear broken and
wavy. If it is possible, compare wool fibres of different weaving
mills. Consider thereby the different appearance of the fibres.
Experts can determine from it the country of origin of wool. Ce-
lanese is like already the name says, artificially manufactured
by a long chemical process. All fibres show hard, dark lines on
the smooth, shining surface. The fibres crinkle after drying in the
same condition. Observe the thing in common and differences.
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